flynx/diff.js
1
0
Fork 0
mirror of https://github.com/flynx/diff.js.git synced 2025-10-28 10:30:09 +00:00
Code Issues Packages Projects Releases Wiki Activity

more docs...

Browse Source 
Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>
This commit is contained in:
Alex A. Naanou 2018-09-26 00:54:40 +03:00
parent 20f9bbe30f
commit 93c2dbdde2
2 changed files with 16 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
README.md
View File

@ -4,8 +4,7 @@ Object diff is a *not-so-basic* diff/patch/pattern/compare implementation for Ja
## Motivation
This module is a re-imagining of *UN\*X `diff`* to support JavaScript object trees in addition to flat text, outputing the result in native JSON. This was intended as a means to locate changes to rather big JSON objects/trees and store them efficiently.
The specific use cases (*[ImageGrid](https://github.com/flynx/ImageGrid) and [pWiki](https://github.com/flynx/pWiki)*) required additional features not provided by the available at the time alternative implementations (listing in next section).
This module was designed and written as a means to locate changes to rather big JSON objects/trees and store them efficiently. Essentially this is a re-imagining of UN\*X [`diff`](https://en.wikipedia.org/wiki/Diff) and [`patch`](https://en.wikipedia.org/wiki/Patch_(Unix)) utilities to support JavaScript object trees in addition to flat text, storing the diff/patch data natively in JSON. The specific use cases (*[ImageGrid](https://github.com/flynx/ImageGrid) and [pWiki](https://github.com/flynx/pWiki)*) required additional features not provided by the available at the time alternative implementations (listing in next section).
## Features
@ -416,6 +415,9 @@ XXX
XXX General description...
Currently *patterns* are designed to not use backtracking when matching.
### Logic patterns
`ANY`
@ -565,9 +567,15 @@ Matches a *container* if it contains `A`.
Matches a *container* if it contains `A` *at* index/key `K`
If `K` is a pattern or a path containing a pattern then matching is done as follows:
1. select all keys/paths that match `K`
2. get all values at the selected keys/paths
3. match iff *all* of the selected values match `A`
1. select all values at keys/paths that match `K`
2. match iff *all* of the selected values match `A`
This may be counter intuitive in some cases, for example consider the following two patterns:
- `AT(OR('x', 'y'), 1)`
- `OR(AT('x', 1), AT('y', 1))`
At first glance they seam to be equivalent but in reality they are quite different as in the first pattern `OR(..)` matches *both* `'x'` and `'y'` keys and thus `AT(..)` will match iff *both* of them are equal to `1`, while the second pattern will match if at least one of `'x'` or `'y'` is `1`.
The first pattern is actually equivalent to `AND(AT('x', 1), AT('y', 1))`.
Note that to use an explicit array for `K`, wrap it in an array, e.g. to use `[item, ..]` as key write: `AT([[item, ..]], ..)`.
@ -757,12 +765,13 @@ For an example see: `Object` handler's `.walk(..)` in [diff.js](./diff.js#L1178)
## The Diff format
For the format structure pattern see [format.js](./format.js).
There are two general format types:
- *Flat* - main and default format used to store diff information.
- *Tree* - used internally but may be useful for introspection.
For the format structure pattern/deffinition see [format.js](./format.js).
## Contacts, feedback and contributions

2
diff.js
View File

@ -788,7 +788,7 @@ object.makeConstructor('ORDERED', Object.assign(Object.create(LogicType.prototyp
// XXX ADJACENT(A, B, ..) == L iff A directly before B, B directly before C, ...
var ADJACENT =
module.ADJACENT =
Dbject.makeConstructor('ADJACENT', Object.assign(Object.create(LogicType.prototype), {
object.makeConstructor('ADJACENT', Object.assign(Object.create(LogicType.prototype), {
__cmp__: function(obj, cmp){
// XXX
},